I use a Microsoft Surface Book 2 with a detachable 13" tablet that is 1.5lb, similar in size and weight to the iPad Pro 13". I get asked to put it away maybe 1 out of 10 times. On BA I have been told that the rule is that electronics need to be smaller in size than the security information card. Into the overhead vs. the seatback is a bit much. A lot of people put their notebook computers in the seatback. But as others have commented, follow all FA commands for your own safety!
I have never seen a college kid reading a textbook asked to put it away.
